U.S. Pat. No. 6,295,994 discloses a mascara applicator comprising a conventional twisted wire core with a plurality of radially extending bristles regularly disposed in a first orientation. A cylindrically configured helix is twisted onto the brush around the wire core so that the brush bristles extend radially between successive loops of the helix. The helix moves at least some of the bristles to a second orientation so as to alter one or more brush characteristics such as mascara retention, mascara application, combing characteristics and brush appearance. The dimensions of the helix, pitch of the helix and thickness of the helix body are preselected to yield the desired characteristics in the finished brush.
U.S. Pat. No. 5,027,838 discloses a cosmetic applicator having a brush with radially adjustable length bristles. The applicator includes a brush head, shaft and sleeve. The brush head has an elongated brush stem with a plurality of bristles circumferentially attached tufts radiating outwardly therefrom. A plurality of perforations are provided in an end of the sleeve through which the bristle tufts are forced to protrude. The brush head and shaft to which the latter is attached are held within the sleeve. When the sleeve is rotated, the bristle tufts protruding through the perforations will wind or unwind around the brush stem, depending on the direction of rotation. In such manner, the effective outward radial length of the protruding bristles tufts can be adjusted.